As we grow older we are supposed to grow wiser. That may or may not be true but it聮s a pretty safe bet that many of us we will grow fatter, heavier and less healthy.
Researchers at the University of Colorado at 麻豆官网 have been looking at why we tend to put on more weight and fat with the years 聟 and what we can do about it.
The research highlights the importance of older people remaining physically active to ward off weight gain and keep at bay associated health risks such as heart problems, high blood pressure, cancer and diabetes.
Traditionally women, especially post-menopausal women, have been regarded as victims of inevitable weight gain as they age. But according to the CU-麻豆官网 researchers, this may not be the case.
A team working in the human cardiovascular research laboratory in the university聮s kinesiology and applied physiology department has found a similar relation between aging, weight gain and metabolic rates for both men and women.
A key focus of the research was something known as the resting metabolic rate (RMR) which accounts for about 70 percent of total daily energy expenditure: energy the body uses just to keep functioning and stay alive.
The primary new finding from this study was that highly fit older people also maintained a higher resting metabolic rate than sedentary older people.
"In other words, if you remain physically active as you grow older you will burn more calories even at rest," said research assistant Professor Pamela Parker Jones. "And that may help prevent weight gain and fat gain with age."
Jones, one of the leaders of the seven-member research team, said RMR decreases with age for both men and women partly because the amount of muscle declines.
As a result, fewer calories are being burned so even though older people tend to eat less, the amount of body weight and fatness still increases.
However, such increases were smaller or even absent among older people who exercised regularly compared to those who were sedentary. Jones said this could be partly due to the energy expended during physical activity but also reflected the effect on RMR.
Another key finding was that highly-active post-menopausal women (those who exercise at least four times per week for between 30 and 60 minutes each time) enjoyed the same RMR as younger physically active women.
"That was important because resting metabolic rate is the main component of energy expenditure," Jones said. "This contributes to the total number of calories you burn each day, which is an important determinant of body weight. It shows that if you remain physically active your metabolic rate stays the same as you get older."
In two separate studies, the researchers looked at about 60 women divided into age groups 21 to 35 and 50 to 72, and 84 men divided by the ages 20 to 35 and 55 to 75.
Each person聮s body fat, fitness level (determined by the body聮s maximal ability to use oxygen) and resting metabolic rate were measured. Researchers then set out to see if people who were physically active showed fewer age-related changes than those who were sedentary.
The two studies found virtually the same pattern for both sexes though men in general had higher RMRs because of their overall higher muscle mass.
Jones said there was still plenty of research to be done in this area but it was clear that for health reasons older people should start or continue exercising to prevent or get rid of excess weight and fat.